Bismuth-Coated Reticulated Vitreous Carbon and Bismuth-Coated Glassy Carbon Electrodes for On-Line Coupling of ASV with ICP-MS

Anodic stripping voltammetry (ASV) has been combined on-line with inductively coupled plasma-mass spectrometry (ICP-MS) using both Bi-coated reticulated vitreous carbon (RVC) and Bi-coated glassy carbon (GC) disk electrodes. Because the same flow cell is used for the RVC and GC disk electrodes, the analytical performances between these two types of Bi-coated electrodes can be accurately compared for their utilizations in the ASV-ICP-MS technique. Comparison of the performances includes signal enhancement, reproducibility, dynamic range, and hydrodynamic stability of the Bi coating. The results indicate that the signal enhancement produced by the Bi-coated RVC electrode (in the flow-through configuration) is greater, while the hydrodynamic stability of the Bi-coated GC disk electrode is better. Both types of electrodes were found to be highly effective in eliminating the matrix effects that are detrimental to ICP-MS analysis. For the purpose of metal preconcentration. Bi has similar properties to Hg (e.g., high hydrogen overpotential and ability to accumulate a range of analytes). However, the Bi film is more robust than the Hg film in a flow system and, unlike Hg2+, Bi3+ in the solution does not cause the memory effect (i.e., it does not adhere onto glass nebulizer and spray chamber of ICP over a long period of time). The nontoxicity of bismuth also makes it an environmentally friendly alternative to mercury for coupling ASV on-line with ICP-based techniques.